Half of savants are autistic; many others gained their gifts through brain injury
Savant syndrome pairs a dazzling talent, often in memory, music, art or calculation, with social or intellectual impairment. It affects around one in a million people. Roughly half are autistic, while the rest usually have brain injury or disease, and a few otherwise ordinary adults have developed the skills suddenly after head trauma.
Skills cluster in five areas: art, memory, arithmetic, music and spatial ability. The commonest type is the calendrical savant, who can name the weekday of any date within a span of decades, or recall what happened on it. Musical savants may show perfect pitch or play several instruments without training, and reports repeatedly link blindness, intellectual disability and musical genius, though nobody knows why. Fewer than one hundred living savants have abilities that would stand out even among people without impairment.
The first medical account dates from 1783. Men outnumber women by about six to one, a wider gap than the 4.3 to 1 seen in autism. Estimates of savant skills among autistic people run from 0.5% to 10%, and when a 2009 British study surveyed 137 parents of autistic children, 28% believed their child had such a skill. Reports describe as many as 50 people whose savant skills appeared suddenly or were acquired, some in older people with frontotemporal dementia.
No single theory explains the blend of talent and deficit. Candidates include a bias toward detail-focused processing, extreme systemising, heightened perception, and obsessive rehearsal of a special interest; a 2012 study found savant children scored higher on obsessions than autistic peers without such skills. Damage to the left anterior temporal lobe can bring on savant abilities, and temporarily switching that region off with low-frequency magnetic stimulation has reproduced them.
John Langdon Down, known for describing Down syndrome, coined the term idiot savant in 1887 after meeting about ten such young people, all male, with feats such as memorising a book after one reading. The label fell out of favour because many cases did not fit the old clinical meaning of idiot, and autistic savant failed too, since only half are autistic. The condition is not listed as a disorder in the DSM-5. Well-known examples include the architectural artist Stephen Wiltshire and the fictional Raymond Babbitt of Rain Man.
Source: Savant syndrome
